Interest invoker

An interest invoker is a link or a button carrying interestfor, which names a popover to show when the reader shows interest in the control and to hide again when they lose it. It is the counterpart of the click half of the same vocabulary, the invoker command, and the same rule holds: the relationship is stated in markup, so the control works before any script has loaded. Status first, because the attribute reads as shippable and is not: this is an Open UI explainer with a pull request open against the HTML specification and an early implementation behind a flag. Design with it, and ship the pattern by hand until it lands.

The attribute is the least interesting part. What is worth a designer’s attention is that the platform is defining what interest MEANS, per input, which is a problem this vocabulary already has a word for. Hover intent exists because a pointer merely crossing a target is a false positive, and every design system that has ever shipped a hover card wrote its own delay, guessed at its length, and got it subtly different from the one next to it. Interest invokers put that number in CSS, as interest-delay-start and interest-delay-end, defaulting to half a second each, so the delay becomes a property a designer sets rather than a timer an engineer buries. The events, interest and loseinterest, fire on the target rather than the trigger, which is the same inversion the command half makes.

The half worth reading twice is touch, because it is the half designers keep getting wrong. A finger cannot hover, so a tooltip wired to pointerenter is a tooltip no phone can open, and shipping one means the extra information exists for mouse users only. The platform’s answer on a touchscreen is a long press, offered through the context menu, with an opt-in ::interest-button pseudo-element for authors who would rather draw an explicit affordance next to the link. A keyboard shows interest by focusing, with the same delay, and Escape always gives it up. Read that as a checklist for anything you build in the meantime: three inputs, three ways in, one way out.

Two fences. This term is the trigger contract, not the surface: what appears is a tooltip, a hover card or some other popover, and those words describe the content and its behaviour once it is up. And interest is not activation. A control that reveals on interest still has to do something when it is actually clicked, which in practice means a link that goes somewhere useful, because a reader who commits to a control expecting the preview to be the whole of it has been misled by the design and not by the attribute.